static void Main(string[] args)
{
Gadget g = new Gadget();
foreach (var gadget in g.GetAllGadgets())
{
// ? is null conditional operator: for not throwing an exception if the value is null
// ?? coalescing operator: for assigning a value of the same type is the current value is null
var name = gadget?.Name ?? "<No Name>";
var price = gadget?.Price ?? 0M;
var releaseDate = gadget?.ReleaseDate ?? null;
var relatedName = gadget?.Related?.Name ?? "<Not Related>";
// $"{}" is string interpolation: {}s are called holess
Console.WriteLine($"name: {name}, price: {price}, releaseDate: {releaseDate}, related: {relatedName}");
}
Car c = new Car();
foreach (var car in c.GetAllCars())
{
var name = car?.Name ?? "<No Name>";
var model = car?.Model ?? "<No Model>";
var category = car?.Category ?? "<No Category>";
var quantity = car?.Quantity ?? 0;
Console.WriteLine(string.Format("name: {0}, model: {1}, category: {2}, quantity: {3}", name, model, category, quantity));
}
Dictionary <string, Car> sportCars = new Dictionary <string, Car> {
{ "Ford", new Car {
Model = "Mustang"
} },
{ "Chevrolet", new Car {
Model = "Corvette"
} },
{ string.Empty, new Car {
} }
};
Dictionary <int, int?> d = new Dictionary <int, int?>();
// index initializer: an easier way for assignment, eliminating { }
var dailyGadgets = new Dictionary <string, Gadget>
{
["Apple"] = new Gadget {
Name = "iPhone"
},
["Dell"] = new Gadget {
Name = "XPS 15"
},
[string.Empty] = null,
["Nokia"] = null
};
foreach (var car in sportCars)
{
Console.WriteLine($"Model: {car.Key}, Name: {car.Value?.Model ?? "<No Model>"}");
}
foreach (var gadget in dailyGadgets)
{
Console.WriteLine($"Model: {gadget.Key}, Name: {gadget.Value?.Name ?? "<No Name>"}");
}
object[] someDate = new object[] {
"Cucumber",
new Car(12)
{
Name = "Benz"
},
new Car(5)
{
Name = "BMW"
},
new Car {
Name = null
},
new Gadget {
Name = "GPS"
},
1201,
12.01M,
null,
int.MaxValue
};
foreach (var data in someDate)
{
// pettern mathcing
if (data is int number)
{
Console.WriteLine($"Number: {number}");
}
else
{
// pattern matching in switch statement: can apply 'when' to add other conditional statements
switch (data)
{
case Car car when car.Quantity > 10:
Console.WriteLine($"Car: {car.Name ?? "<No Name>"} has more than 10 times of copies");
break;
case Car car when car.Quantity == null:
Console.WriteLine($"Car: {car.Name ?? "<No Name>"} has no clear number of copies");
break;
default:
Console.WriteLine($"Other: {data ?? "<No Value>"}");
break;
}
}
}
}
